The objectives of this study were to investigate dental caries status and high caries risk predictor of 7-grade secondary schoolchildren. This cross-sectional analytical study involved a sample of 190 schoolchildren. School random sampling was used to recruit children from private Islamic religious schools in Ruso district. Modified oral examination form and oral health behavior questionnaire from World Health Organization and previous study were used for data collection. The chi-square and logistic regression were analyzed to investigate high caries risk predictor. The results found that dental caries prevalence was 89.5 % given the DMFT of 3.69 ± 2.82, and decayed tooth was the main component. The children reported that they frequently brushed their teeth at least twice a day 83.7 %. They also cleaned their teeth before every prayer. They consumed sugary food between meals 70.5 %. Almost of them visited the dentist during the last one year and dental check-up was the most common reason for the dental attendance, and scaling was the most common received treatment. Data analysis showed a statistically significant association between the high caries status with none of oral cleanliness before Zuhr prayer (OR: 2.45; 95% CI: 1.21-4.99) and none of appointment for dental treatment (OR: 0.46; 95% CI: 0.23-0.92). In conclusion, schoolchildren in private Islamic religious schools in Ruso district had high caries prevalence and severity. Oral cleanliness before Zuhr prayer was the strongest risk predictor of high caries status, followed by attending every appointment for dental treatment.